A sublaminate analysis is used to develop an analytical solution that determines the effect of midplane internal delamination on unsymmetric elastically tailored laminated plates. A displacement field that recognizes transverse shear deformation is proposed, and an elasticity boundary value problem is developed. A force-deformation relationship for the delaminated plate is derived. A change in total strain energy release rate and extension-twist coupling with crack length is calculated. The distribution of interlaminar shear and peel stresses on the interface containing the delamination is determined. The analysis is applied to a class of hygrothermally stable unsymmetric laminates under uniform extension. Results show that extension-twist coupling decays monotonically and total strain energy release rate increases monotonically, respectively, with delamination width. Interlaminar shear and peel stress are shown to be of larger magnitude at the free edge than at the delamination tip. The variation of extension-twist coupling with delamination width was verified experimentally. Test results indicate that for the cases under consideration, Teflon FEP film is inadequate for the simulation of internal delamination.